Slo mo strobbing help at DVinfo.net

Denise Wall · November 19th, 2011, 09:28 AM

Using FCS3 and 2010 mac pro. I was shooting action stills with my 7D when I came upon a situation where I felt I could capture unique footage by video. Not having any time to fiddle with settings, I just switched modes and captured video at way too high of a shutter speed for smooth video. Otherwise okay footage. Now I'm in a situation where I want to use a short clip of this video in variable slo mo but of course I'm getting strobing (I think that's what it's called) from the fast shutter speed. I tried blurring the frames but not much joy there. It's okay if it's a bit blurry as long as I can cut down on the strobing. Any other suggestions?

John Wiley · December 5th, 2011, 03:50 AM

What format/frame rate did you shoot at?

If you shot at 50p or 60p, then you need to use Cinema Tools to conform your footage to 24p, 30p, or 25p (depending on your timeline). Then when you import it into FCP and drop it on your timeline it will automatically play in slow-motion.

If you shot at 24p, 25p or 30p, then the best looking slow motion will be achieved by using motion estimation with a program like Twixtor or After Effects. This invloves the software creating in-between frames by analysing the pixel motion on a frame by frame basis. However, it only works effectively if you have a fairly sharp image all over. If you were shooting at a really high shutter speed as you said, then you probably also had a wide aperture, in which case there will be a lot of out-of focus areas which the motion estimation will really struggle with.

Denise Wall · December 5th, 2011, 08:39 AM

Hi John,

Thanks for your reply. I was shooting 30p so I didn't have the advantage of sending it to Cinema tool like I've done before when I knew something was destined for slo mo and shot at 720 60p. I went back and looked at it just now and the even though the shutter speed was quite high, probably at 1/1000 (set for action stills) the aperture must've been at around f8 because the background is in pretty good focus. However, the background is trees and grass which taxes the codec. So I'm not sure how much increase in quality I would've seen no matter how sophisticated the tools.

At this point, I've already delivered the final product with the best slo mo I could but manage in that few seconds of the entire 11 minute educational/promotional video. I'm sure my eye is more critical than the target audience for this video. However, I've been thinking about Twixtor for a long time - wondering if I do enough slo mo to make it worth it. Is it easy to use?

November 19th, 2011, 09:28 AM	#1
Denise Wall Regular Crew Join Date: Mar 2008 Location: Advance, NC Posts: 153	Slo mo strobbing help Using FCS3 and 2010 mac pro. I was shooting action stills with my 7D when I came upon a situation where I felt I could capture unique footage by video. Not having any time to fiddle with settings, I just switched modes and captured video at way too high of a shutter speed for smooth video. Otherwise okay footage. Now I'm in a situation where I want to use a short clip of this video in variable slo mo but of course I'm getting strobing (I think that's what it's called) from the fast shutter speed. I tried blurring the frames but not much joy there. It's okay if it's a bit blurry as long as I can cut down on the strobing. Any other suggestions? Last edited by Denise Wall; November 19th, 2011 at 10:40 AM.

December 5th, 2011, 03:50 AM	#2
John Wiley Trustee Join Date: Oct 2008 Location: Byron Bay, Australia Posts: 1,155	Re: Slo mo strobbing help What format/frame rate did you shoot at? If you shot at 50p or 60p, then you need to use Cinema Tools to conform your footage to 24p, 30p, or 25p (depending on your timeline). Then when you import it into FCP and drop it on your timeline it will automatically play in slow-motion. If you shot at 24p, 25p or 30p, then the best looking slow motion will be achieved by using motion estimation with a program like Twixtor or After Effects. This invloves the software creating in-between frames by analysing the pixel motion on a frame by frame basis. However, it only works effectively if you have a fairly sharp image all over. If you were shooting at a really high shutter speed as you said, then you probably also had a wide aperture, in which case there will be a lot of out-of focus areas which the motion estimation will really struggle with.

December 5th, 2011, 08:39 AM	#3
Denise Wall Regular Crew Join Date: Mar 2008 Location: Advance, NC Posts: 153	Re: Slo mo strobing help Hi John, Thanks for your reply. I was shooting 30p so I didn't have the advantage of sending it to Cinema tool like I've done before when I knew something was destined for slo mo and shot at 720 60p. I went back and looked at it just now and the even though the shutter speed was quite high, probably at 1/1000 (set for action stills) the aperture must've been at around f8 because the background is in pretty good focus. However, the background is trees and grass which taxes the codec. So I'm not sure how much increase in quality I would've seen no matter how sophisticated the tools. At this point, I've already delivered the final product with the best slo mo I could but manage in that few seconds of the entire 11 minute educational/promotional video. I'm sure my eye is more critical than the target audience for this video. However, I've been thinking about Twixtor for a long time - wondering if I do enough slo mo to make it worth it. Is it easy to use?